The overall goal of this project remains the delineation of neural systems underlying language, by means of special experiments conducted in patients with focal brain damage. The first specific aim is to map the neural basis of the lexicon. The studies focus on the systems supporting lexical access, which we hypothesize to be based on left temporal cortices. The second specific aim relates to the processing of visuomotor linguistic signs, such as those used in American Sign Language (ASL). We will investigate the neural systems required for representing and accessing such signs, by studying the acquisition of ASL lexicon in hearing patients with a wide range of focal damage in left and right hemispheres. Also, we will continue to assess the clinical value of traditional diagnostic categories of aphasia, by investigating the consistency of anatomo-clinical correlations in our database, and to study the neural basis of auditory perception. The results will contribute to a more precise formulation of the neural basis of language, at systems level, and in particular, to further specification of the neural and cognitive architectures pertaining to lexical access and lexical representation. The results will shed light on the diagnosis and physiopathology of the aphasias, and assist in the development of programs to rehabilitate the large number of stroke and head injury victims who develop language impairments. Our approach capitalizes on the unique opportunities afforded by the study of adult humans with focal brain injury, and seeks to advance knowledge of language at both the neural and psychological levels.